MIX 1/3 cup barbecue sauce and horseradish until well blended.
THREAD meat onto 18 skewers; place onion or pepper strip at end of each skewer. Place kabobs in shallow glass dish. Pour sauce mixture over kabobs. Refrigerate 1 hour to marinate, turning occasionally.
HEAT barbecue to medium heat. Remove kabobs from marinade; discard marinade. Grill kabobs 4 to 6 min. or until meat is done, turning occasionally. Brush remaining barbecue sauce for the last 2 min.